CJH332H1 Lecture Notes - Lecture 1: Pyramidal Cell, Social Defeat, Cerebral Cortex
Lecture 1: Introduction to Synaptic Neurobiology
Neurobiology of stress
• Stress is processed at the level of cerebral cortex, activating the medial prefrontal, anterior cingulate cortex,
amygdala and hypothalamus (produces physiological response)
- Important in anxiety and depression
• Short term stress is good – release of NE from locus coeruleus
Animal models of stress
• Acute (beneficial) and chronic (detrimental) forms of stress and both physical and psychosocial forms of stress
cause release of glucocorticoids (stress hormone)
• Various forms of stress and the duration of stress on different animals cause changes in the synapse, neurons in
various areas of the brain, their circuits and behavior
- Physical stress (immobilization or restrainer)
- Psychosocial stress (predator odor, elevated platform, social defeat or maternal separation)
• Different circuits have different weakening effects
Stress affects multiple brain areas
• Interplay between NAc (influenced by VTA) and mPFC
• Amygdala – spiny neurons most dominant
• NAc – medium spiny neurons (respond in the same way as amygdala spiny neurons?)
• VTA – dopaminergic neurons
• CA3 (hippocampus) – pyramidal
neuron respond to anxiety and
stress
• mPFC – pyramidal neuron
• Do they respond in the same way
even in same classification?
Depends on the location?
Affects on morphology/function
• Growing of neurons means an over-
activation of the neurons
(hypervigilant) after exposure to
stress
• Dopaminergic neurons shrinks –
losing interest
• Hippocampus neurons shrinkage –
memory affected in bad way
- Some individuals undergoing
anxiety makes association with
traumatic events (PTSD
relation?)
- Cannot concentrate as well (mPFC)
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Document Summary
Neurobiology of stress: stress is processed at the level of cerebral cortex, activating the medial prefrontal, anterior cingulate cortex, amygdala and hypothalamus (produces physiological response) Important in anxiety and depression: short term stress is good release of ne from locus coeruleus. Psychosocial stress (predator odor, elevated platform, social defeat or maternal separation: different circuits have different weakening effects. Affects on morphology/function: growing of neurons means an over- activation of the neurons (hypervigilant) after exposure to stress, dopaminergic neurons shrinks losing interest, hippocampus neurons shrinkage memory affected in bad way. Some individuals undergoing anxiety makes association with traumatic events (ptsd relation?) If corticosterone is elevated, it causes rapid glucocorticoid receptor-mediated increase of presynaptic snare protein complexes (mediates fusion of synaptic vesicles) in the presynaptic membrane. Why the complicated stress response: steroids can interact and cause genomic changes that are difficult to track in individuals.
